51.   Scientists have learned how bacteria can build up in gaps in the gum, cause infection, weaken the jawbone, and eventually murder teeth.

52.   Scientists learned, for example, how to quickly manufacture thousands of doses of penicillin.

53.   Scientists are learning, for example, that the genes of cows, dogs, rats, people and all other mammals are extremely similar.

54.   Scientists are still learning how stem cells differentiate into other tissues.

55.   Scientists have learned much about how cholera is transmitted by feces, food and water.

56.   Scientists have learned much from the newly designated Valles Caldera National Preserve.

57.   Scientists were learning how the cancer cell differs from normal cells, an understanding that often was advanced as much through their failures as their successes.

58.   Scientists had learned that the normal product of the gene is a protein called huntingtin that is produced throughout the brain and body, but whose function is unknown.

59.   Scientists learned the findings on Monday at a meeting of a committee that oversees the safety and effectiveness of such studies.

60.   Scientists must learn to speak to the public in terms they understand about the importance of the work they are doing.